1. Field of the Invention
The present invention relates to a wiring substrate having circuit components or the like mounted therein, a connection structure of wiring substrates, and a method of connecting wiring substrates, and particularly relates to wiring substrates electrically connected to each other by superimposition, a connection structure of wiring substrates, and a method of connecting wiring substrates.
2. Description of the Related Art
Hitherto, electronic circuit devices have been known in which two printed wiring substrates having electronic circuit components mounted therein are superimposed on each other, and connection terminals of each printed wiring substrate are electrically bonded to each other.
Incidentally, in the electronic circuit devices, when it is confirmed whether the operation of electronic circuit components mounted in each printed wiring substrate is normal, connection terminals of each printed wiring substrate are temporarily bonded to each other by thermo-compression bonding or a conductive adhesive, and the confirmation is performed. When the operation of the electronic circuit components is normal, temporary bonding of the connection terminals serves as main bonding as it is.
However, when the operation of the electronic circuit components is not normal and the electronic circuit components are required to be replaced, the thermo-compression bonding state of the bonding terminals is eliminated, or the conductive adhesive is peeled off, and thus the temporary bonding of the connection terminals is resolved. A method is taken in which each printed wiring substrate is returned to a state before the connection to replace the electronic circuit components with new ones, and then the connection terminals of the respective printed wiring substrates are reconnected to each other.
As described above, when a method is taken in which, after the connection terminals of two printed wiring substrates having electronic circuit components mounted therein are temporarily connected to each other, the connection state of the connection terminals is eliminated, and main connection of the connection terminals is performed again, the bonding strength of a compressed portion between the connection terminals becomes weaker, or the bonding state of the connection terminals becomes unstable due to the conductive adhesive remaining in the vicinity of the connection terminals, and thus it is difficult to obtain a stable electrical connection state between the respective connection terminals.
Such a problem is also present in a technique disclosed in the Japanese Unexamined Patent Application Publication No. 2014-96531. In Japanese Unexamined Patent Application Publication No. 2014-96531, an adhesive film is temporarily bonded onto a printed wiring substrate, the adhesive film is temporarily peeled off when a shift occurs at the attachment position of the adhesive film, and the adhesive film is bonded to the printed wiring substrate again after position adjustment.
Incidentally, when an electronic circuit component is required to be replaced in adjustment during temporary connection between connection terminals of a printed wiring substrate, it is also considered that an electronic circuit component operating normally is mounted in a new printed wiring substrate, and that the respective connection terminals are reconnected to each other. However, in such a connection method, replacement with a new printed wiring substrate is required to be performed, which leads to an increase in the cost of an electronic apparatus.